1. Field of the Invention
This invention generally relates to integrated circuit (IC) fabrication and, more particularly, to a method of consuming oxidation that occurs in the formation of a silicon (Si) nanoparticle film.
2. Description of the Related Art
Low temperature and low thermal budget processing for large area electronics is gaining momentum with many recent advances involving non-vacuum deposition, etching steps (such as printing), and roll-to-roll, low-cost techniques on flexible substrates. One way to form the active semiconductor film for a thin-film transistor in such a printing-compatible process is by the use of Si, or other semiconductor, in the form of a nanoparticle liquid suspension (termed nanofluid suspension). Particle sizes for Si can range from <1 nm to >100 nm, based on the desired application. This process typically involves the selective deposition of the nanofluid, and one or more elevated temperature steps aiming at the evaporation of the various solvents of the suspension and the sintering of nanoparticles to form an interconnected porous nanoparticle film and/or a homogeneous semi-conducting film.
One problem common with the processing of Si nanofluids is the spontaneous formation of silicon dioxide on the surface of the nanoparticles. A thin oxide forms within seconds after exposure in air in ambient temperature. Thicker oxides form during the aforementioned elevated temperature steps, if they take place in an oxidizing environment. This oxide can easily reach thicknesses that severely limit the conductivity of the semiconductor, and can also severely limit the sintering process. One solution to this problem is to prevent the exposure of the nanofluid to an oxidizing environment until sintering is accomplished. While feasible, this certainly entails increasing the level of complexity and sophistication of the processing steps (i.e. processing in low pressure, inert gas atmosphere, etc.), which runs counter to the quick-and-inexpensive target of this approach.
It would be advantageous if semiconductor nanoparticles films could be formed in a low complexity process, without forming semiconductor oxide products.